I have 4 clowns and 5 botia in a 230 with no problems. I think 50 gallon might be to small.
I would have to agree that a 50g is too small for the clown's. I have 10 clowns, 10 bermese, 10 striata in a 170g no issues. Have you thought about straiata's, bermese, skunk, chain loaches? They stay smaller and would do better in a 50g.